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BRAVO 25 DESCRIPTION
Bravo 25 is located near the eastern end of Bravo wharves 22 through
26 in the Southeast Loch across from Merry Point of the NAVSTA.
It is a cast-in-place, reinforced concrete deck and superstructure
supported by precast concrete piles. The Bravo wharves are over
50 years old. Bravo 25 is 550 feet (168 m) long and 37 feet (11
m) wide. Bravo wharves were originally designed to support 50-ton
(45 metric ton), rail mounted, portal cranes, train cars, as well
as 900 pounds per square feet (43 kPa).
The design strength of the concrete was 3,000 psi (20 mPa) and
the reinforcing steel is ASTM grade 40. Two continuous girders (pile
girders) that were cast on top of two rows of piles (Figure
4) support an abandoned crane rail system and the deck.
The piles are spaced 4 feet (1.2 m) on center. The piles are 18
inches (46 cm) square and have a design capacity of 40 tons (360
kN) each. Each bent has a transverse girder that spans between the
two pile girders at 12 feet (3.7 m) on center. The transverse girders
are 5 feet (1.5 m) deep and are reinforced with 14 - number 8 bars
(25-mm diameter) at the bottom. Spanning between the transverse
girders and parallel to the pile girders are two wide stringers
(track slabs) (5 feet 6 inches (1.68 m) wide and 1 foot 8 inches
(0.5 m) thick) which carry abandoned train rails (two rails per
stringer). Reinforcement in the track slabs consists of 12 number
7 bars (22 mm diameter) at midspan and 8 number 7 bars (22 mm diameter)
over the transverse girders. The deck is 8-1/2 inches (22 cm) thick
between the track slabs and is reinforced on the bottom with number
5 bars (16 mm diameter) at 6 inches (15 cm) on center and number
3 bars (10 mm diameter) at 5 inches (8 cm) on center outside the
track slabs. Number 4 bars (13 mm diameter) reinforce the deck longitudinally.
That part of the deck with the curb that cantilevers out from the
outboard pile girder (curb slab) is 13-1/2 inches (34 cm) thick
and is reinforced with number 6 bars (19 mm diameter) at 5 inches
(13 cm) on center. The top reinforcing bars are bent down and anchored
below the outboard crane rail. The top transverse reinforcing is
not continuous because of the crane and train rails. Figures
5 and 6 are graphics of existing
reinforcing steel.
Track mounted cranes have been replaced on the Bravo wharves by
truck mounted, mobile cranes. Mobile crane load limitations currently
placed on Bravo wharves are very restrictive. A Public Works Center
(PWC) waterfront load study of January 1994 by Tanimura and Associates
(Contract No. N62755-90-D-0920) limits crane outrigger loads to
the track slabs and the rail girders. Other areas are restricted
to truck and forklift wheel loads. Maximum uniform live load is
limited to 490 psf (23 kPa).
Figure 4. Typical cross section of Bravo
25.
Figure 5. Typical deck reinforcing details
at midspan between transverse girders.
Figure 6. Typical reinforcing details of
the transverse girder.
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